[Rd] typo in nls.Rd

[Katharine Mullen]

in R version 2.5.0 Under development (unstable) (2007-02-25 r40804),
the `formula' entry in the `arguments' section of nls.Rd (L25-26) reads

\item{formula}{a nonlinear model \link{formula} including variables and
    parameters.  Will be coerced to a formula is necessary.}

`is' should be `if'.

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Katharine Mullen
Department of Physics and Astronomy
Faculty of Sciences
Vrije Universiteit Amsterdam
de Boelelaan 1081
1081 HV Amsterdam
The Netherlands
room: T.1.06
tel: +31 205987870
fax: +31 205987992
e-mail: kate at nat.vu.nl
http://www.nat.vu.nl/~kate/